Conveyor slack take-up mechanism



March 16, 1948. s. M. MERCIER CONVEYOR SLACK TAKE-UP MECHANISM Filed Aug. 19,

IN V EN T OR, STANLEY M. MEE'CIEE,

Patented Mar. 16, 1948 ATEN'I? QONYEYOR SLACK TAKEH-URMECHAN-ISM Stanley Mercier, Bexley, Ohio, assignorpbti, mes'neassignments, to The Jeffrey Manuface turing co npany. a corporation of Ohio Application August 19, 1944, Serial No. 550,259e

(Cl. 19,8 2G8l.

'7 Claims. 1

Th s i nr e i iq-.esqnrerprl a n- Veyor. t 2 d fi ir i liie i z h n e tmni to provide aconveyor including a imkfl-up'mechanisin ,whicliacts to" m aintainphain or chains of the conveyor under 'proper s1on .or,; in other words, to take up ltheislaclg ,while providing for free movement of the take-up mechanism; in one direction I andv only restricted; or slowmovement thereof infthe opposite direction A further .object l of th e ir vention is to provide.

a conveyor s'ystemiiricluding aplurality of endless chains, each .having' angindividual associated take-up mechanisrnfof theacharacter above-described, each take-up mechanism including a hydraulic piston motor supplied .with hydraulic fluid from. a veommonfisource; andin which each piston motor canmove. freely to expand but can contractonly at a restricted rate and in a complete aspect of my invention thehydraulic system includes a pressure relief valve operable in response to. apredetermined. highpressure on any take-up device and -infl whiplr there may or may not be signal oncontrol means operated by actuation of the pressure relief valve Other objects of theinven-tionwill appear hereinafter, the novel features and combinations being set forth in the. appendedclairns In the faccompanying.drawings.-

Fig. 1 is a diagrammatic view-showing two conveyors in tandem,...th'e con veyors preferably incorporating theflfeatu'res of myinvention;

Fig. 2 is an enlarged elevational View of one strand of chain ofone of the conveyorsincorporating the features oijmy invention;

Fig. 3 is a transverse sectional viewtaken on the line 33 of .Fig. 2',".loohingin the direction of the arrows;

Fig. 4 is a transversesectional view taken on the line 4-4, of Fig.. 2; "an

Fig.5 is a scheniatic pip ng diagram of the hydraulic system of my; invention. 5

The invention.herein disclosed designed to solve a problemtwhich wasv encountered in connection with the conveying ofhot sheets-of steel by a plurality of successiveconveyors. The hot sheets of steel heat :the chains-of the individual conveyors and often individual chainsare subject to entirely different temperatures and the temperature of any individual chain-Will vary appreciably from time to time'causlng expansion and contraction thereof.

As an additional factor, sometimeswhen the started at all, so. that the-drivenrconveyor.tended to drive the chains of. thegother conveyor. ,This} tended to produce slackinthe tuppezgoreworking run of the other conveyor and tq thrpwethelchain off its driving sprocket...

In Fig. 1 of the drawings. I have illustrated-diagrammatically two successive conveyors-,1 0 -.and 1 i l. Each of thesenconveyors is.rdrivenfgentirelyt independently of the other andz inlthe particplar... installation wherein my ;invention.nwas :madw the conveyors H1 and I l convey-sheetspi hot steel as above mentioned. Each ponveyorelfi rand..l I consists ofa plurality of indiyiduahstranddasof chain and in the particular. installationinvolved there were six strandsof .chain on; .eachconveyom ii! and \I L. Each of thesejchain-s wasdriyen from a common drive shaft. through} an; individual.- sprocket." The foot sprockettof;eaclr oithechains wasmounted loosely on a commonsl'laft.andtln s was individually rotatable ongsaidshaft;

In Figs. 2, 3 and 4 of thedrawings-I have illustrated in detail the..constructionmflone ,oi the strands of chainof the ,conv'eyor lll' -it'abeing understood that in the co mpletegponveyor :there are a plurality of suchstrandsdrivendrorn.the. same head shaft through individual sprgoolqats1. Thatis, a head shaft 12,- isap fqvidedacarryingsix drive or head sprockets; oneof,which is seen at iii. The ead s t 2 T FmQ QWd F iE EWmQ bearings, one ofwhichisseenat lj cariried on an:- I-beam l5.

Extending around and; driven by thasprpcket; i3 is an endless chain 6; thempper orsworking strand orrun of which, is supported on an .I-he'am which in n suppor ont pro riate frame members in cludingyl beams 48 At its rearvend the chaini;lfi v travels around.

a footwheelor sprocketJS mountedgon; a foot;

shaft 20. As previously mentioned hereswill-lze six sprockets i9 each mounted:ioreindependent rotation onthe .footshaftlfl Foot shafteflgis supported in appropriate bearings,,one..of which. isseenat2l.

It is L desirablev .to.provide;;.-a .slaclg takjeeup mechanism individuah-toeach chain l 6 ,ewhichd will keep it under proper-tensions-withou ,=over.- loading it while providingfor fre eexpansiorrtand: contraction thereof; due -,-t0 changes :in ,-tempe ra-. ture and dueto wear which,takefplaearelatiyely slowly. Asia matter of fact,.-the-take;-.up meoh m. nism will compensate. vion expansion tevemat 5a rapid rate, but restrictsthecontra on to;; that=. at a slow rate.- The-takeeupsrnechanismds duplicated for each. of the chains l 6 and. each; includes a. hydraulic, pistonwmotorezz-includinaa oil-linden;

3 23 and a piston rod 24 extending into said cylinder. The piston rod 24 carries a piston at its upper end, and the lower end is pivoted by a pivot pin 25 to a curved pivotally mounted weighing member 26 which may be in the form of a rail pivotally attached by a pivot pin 21 to a pair of spaced-apart plates 28 forming a part of the conveyor frame. The cylinder 23 is also provided with trunnio'ns 29 by which it is pivotally attached between the spaced plates 28.

By reference to Fig. 2 of the drawings it is obvious that the weight of the weighing member 26 will take up the slack in the chain I6 which is accumulated directly to the rear of sprocket I3 and on the return run of said chain l6.

It is, of course, desirable that the weight trans mitted by the member 26 be not excessive, or it will cause undue wearing of the chain l6. At the same time it should be adequate to take up the slack in the chain l under all conditions or, in other words, should keep the chain l6 under proper tension. The two extreme positions in which the take-up mechanism in chain l6 may be found are illustrated in full lines and in dotted lines in Fig. 2 of the drawings.

The take-up piston motors 22 associated with the six strands of the conveyor ID are illustrated in Fig. 5 of the drawings. The upper ends of all of the cylinders 23 are connected through individual valves 30 to a hydraulic feed line 3| which is connected with a hydraulic tank 32. The connection between the tank 32 and line 3| includes a check valve 33 which permits the hydraulic fluid to flow freely from the tank 32 to the line 3| and thus freely to any cylinder 23 whose valve 30is open, thereby providing for free expansion of the piston motors 22. Normally, all of the valves 30 will be open, any valve 30 being operable to closed position to disconnect the associated take-up mechanism.

Also between tank 32 and feed line 3| is a variable throttle valve 34 which controls the rate at which hydraulic fluid can flow from the line 3| back into the tank 32. This therefore controls the rate of contraction of the hydraulic piston motor 22.

There is also a pressure relief valve 35 connected between the tank 32 and the feed line 3| so that in case there is an excessive pressure in line 3|, caused for example by an undue or excessive load on a piston motor 22, the relief valve 35 will open and permit the fluid to flow from feed line 3| into the tank 32. If desired, a switch may also be operated by the relief valve 35 whenever it opens, to close an electric circuit 36 which may include an alarm or buzzer 31 and an operating relay 3-8 which may shut down the driving motor for a conveyor. The circuit 36 may-be eliminated if desired.

In the operation of the system hot plates will be delivered, for example, to the conveyor l0 and by it to the conveyor The endless chains l6, of which there are six in the embodiment illustrated in each of the conveyors l0 and II, will carry the hot plates and will absorb some of the temperature thereof. This heating of the chains |6 will cause them to expand and the take-up mechanism will maintain the chains under proper tension when so expanded. As the chains l6 contract under cooling or reduced temperature, the take-up mechanism will accommodate this condition, since the'hydraulic fluid can flow at a slow rate through the throttle valve 34.

Should a condition arise, for example, in which the conveyor H is not being driven or is being driven at a lower speed than the conveyor l0, through inadvertance, the plate or sheet conveyed by conveyor l0 might possibly drive the upper or working run of the conveyor II. This would, of course, tend to take up the slack from the lower run at a very rapid rate and if this were permitted, it is entirely probable that the accumulation of chain on the upper run would cause the chain to jump the sprocket l3. This is prevented, however, by the snubbing action of the take-up mechanism since it can only contract at a relatively slow rate. Should a high pressure situation develop in the line 3|, for example, by the extreme hard pushing of the upper run of one of the chains l6, the pressure relief valve 35 would open to relieve the undesirable pressure condition, and if the alarm system or circuit 36 is employed, this will also give a signal and/or shut off a driving motor if one is controlled by relay 38.

Obviously those skilled in the art may make various changes in the detail-s and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and'shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. A conveyor including an endless chain, slack take-up mechanism associated with said chain for taking up slack therein, said mechanism being constructed and arranged to operate to provide for free expansion and slow contraction of said chain while preventing rapid contraction thereof, said mechanism including a cylinder having a piston therein, valve means associated therewith operable to provide for free outward movement,

of said piston as fluid flows freely into said cylinder and restricted inward movement, and an overload relief valve operated in response to an excessive pressure of the fluid in said cylinder.

2. A conveyor including an endless chain, slack take-up mechanism associated with said chain for taking up slack therein, said mechanism being constructed and arranged to operateto provide for free expansion and slow contraction of said. chain while preventing rapid contraction thereof, said mechanism including a cylinder having av piston therein, and check and high pressure relief valve means associated therewith operable to provide for free outward movement of said piston as fluid flows freely into said cylinder and restricted inward movement.

3. A conveyor including a plurality of endless chains, means for driving each of said chains together, individual slack take-up means for each chain, said take-up means each including a hydraulic piston motor, means for feeding hydraulic fluid to all of said motors to provide for their free expansion to take up slack in their associated chains, means providing for restricted contraction of each of said motors, and means responsive to an excessive pressure created by any one of said motors for relieving the pressure of the hydraulic feed means and for actuating a control device.

4. A conveyor including a plurality of endless chains, means for driving each of said chains together, individual slack take-up means for each chain, said take-up means each including a hydraulic piston motor, means for feeding hydraulic fluid to all of said motors to provide for their free expansion totake up slack in their associated chains, means providing for restricted contraction of each of said motors, and means responsive to an excessive pressure created by any one of said motors for relieving the pressure of the hydraulic feed means.

5. A conveyor including a plurality of endless chains, means for driving each of said chains together, individual slack take-up means for each chain, said take-up means each including a hydraulic piston motor, means for feeding hydraulic fluid to all of said motors to provide for their free expansion to take up slack in their associated chains, and means common to all said hydraulic piston motors providing for restricted contraction of each of said motors.

A conveyor including an endless chain, slack take-up mechanism associated therewith for taking up slack therein and including a fluid pressure piston motor,- check valve means associated with said piston motor providing for its free expansion, throttle valve means providing for controlled contraction thereof, and valve means providing for its rapid contraction in response to excessive overload.

7. Apparatus of the class described, including endless conveyor means, take-up means therefor including an expansible fluid motor having a piston and cylinder and operable upon expansion thereof to take up increased slack in said convey-or means, means for controlling flow of fluid to and from said cylinder as the piston moves relative thereto including a check valve providing for free expansion of said piston and cylinder while preventing free contraction thereof, and a pressure relief valve adapted to open and provide for contraction of said piston and cylinder in response to a predetermined pressure of said fluid caused by said conveyor means tending to reduce the apparent amount of slack.

STANLEY M. MERCIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,663,344 Lennard Mar. 20, 1928 2,191,946 Weller Feb. 27, 1940 

